<template>
<el-tree
  :data="data"
  node-key="id"
  default-expand-all
  @node-drop="handleDrop"
  draggable>
</el-tree>
</template>
<script>
  export default {
    data() {
      return {
        data: [{
          id: 1,
          label: '一级 1',
          children: [{
            id: 4,
            label: '二级 1-1',
            children: [{
              id: 9,
              label: '三级 1-1-1'
            }, {
              id: 10,
              label: '三级 1-1-2'
            }]
          }]
        }, {
          id: 2,
          label: '一级 2',
          children: [{
            id: 5,
            label: '二级 2-1'
          }, {
            id: 6,
            label: '二级 2-2'
          }]
        }, {
          id: 3,
          label: '一级 3',
          children: [{
            id: 7,
            label: '二级 3-1'
          }, {
            id: 8,
            label: '二级 3-2',
            children: [{
             id: 11,
              label: '三级 3-2-1'
            }, {
              id: 12,
              label: '三级 3-2-2'
            }, {
              id: 13,
              label: '三级 3-2-3'
            }]
          }]
        }],
        defaultProps: {
          children: 'children',
          label: 'label'
        }
      };
    },
    methods: {
      handleDrop(draggingNode, dropNode, dropType, ev) {
        console.log('tree drop: ', dropNode.label, dropType);
        console.log(this.data);
      }
    }
  };
</script>